This invention relates to a vibration exciting apparatus which performs a vibration exciting testing of multiple degrees of freedom and a vibration testing system. This vibration testing system examines a vibration exciting motion for a part of a structure experimentally by using the vibration exciting apparatus, calculates a vibration exciting motion for another part of the structure with a numerical calculation of vibration response and calculate a vibration exciting motion for a whole of the structure by combining them.
An example of the vibration test of the structure is mentioned in JP-A-5-10846. This vibration testing system performs a vibration exciting testing for a part of the structure experimentally, executes a numerical calculation of vibration response for the other parts of the structure, and performs a testing for the whole of the structure by combining them. The method mentioned in this publication performs a vibration exciting testing by using one vibration exciting machine in real time.
An apparatus for applying a load in a translational direction and a rotational direction to a body to be tested is mentioned on page 581 of the 43rd Nat. Cong. of Theoretical and Applied Mechanics, 1994.
The apparatus mentioned in JP-A-5-10846 is based on the case that a prototype model is deformed in only one direction and moreover any one of the following assumptions is established. One assumption is that a rigidity of a floor in a building is very large in comparison with a rigidity of a wall, and a bending deformation of the floor can be negligible. Furthermore, a rigidity of the wall in-plane deformation is large in comparison with a rigidity of the wall out-plain deformation, so that an expansion and compression of the wall can be negligible. Another assumption is that a prototype model is supported on both end portions without taking moment.
However, according to the invention analysis that is a part of the present invention, an actual piping system, pier, vibration isolation apparatus and the like are structures transformed in both of the translational direction and the rotational direction. Therefore, it is desirable to perform a vibration excitation with respect to the prototype models in the translational direction and the rotational direction. However, in the apparatus mentioned in JP-A-5-10846, there is no consideration of the structure of applying the vibration excitation in both directions. Therefore, it was difficult to know these vibration exciting motions precisely.
On the other hand, in the case of the present invention in which the vibration excitation can be performed in the translational direction and the rotational direction with respect to the prototype model, a vibration exciting machine having a large mass swing, and a force of inertia and the elastic force of the oil hydraulic pipe acts as a disturbance with respect to the vibration excitation. Therefore, there is a problem that vibration excitation precision is decreased. Furthermore, in this apparatus, since the vibration exciting machine was arranged inside a reaction force frame, it has been hard to make the reaction force frame compact and of high rigidity.
The invention was arrived at by taking the problems of the prior art mentioned above into consideration, and an object of the invention is to provide a vibration exciting apparatus capable of testing a structure which deforms in both of a translational direction and a rotational direction and a vibration testing system using the same. Another object of the invention is to provide a vibration exciting apparatus which has an improved accuracy of a vibration excitation, a compact size and a high rigidity and which is used for a vibration testing system.
In order to achieve the object mentioned above, in accordance with a first aspect of the invention, there is provided a vibration testing system for a structure, which is provided with a vibration exciting apparatus for causing a vibration excitation for a prototype model imitating a part of the structure and a control calculating apparatus for calculating a vibration response of a numerical model imaginarily connected to the prototype model, and performs a vibration testing of a whole of the structure, wherein the vibration exciting apparatus is provided with a plurality of vibration exciting means for causing a vibration excitation of the prototype model, a plurality of displacement detecting means for detecting displacements of the plurality of vibration exciting means and load detecting means for detecting a load applied to the prototype model, and the control calculating apparatus is provided with calculating means for calculating displacements in a translational direction and a rotational direction of a point of exciting force previously determined on the basis of the load detected by the load detecting means and the displacement of the vibration exciting means detected by the plurality of displacement detecting means, and signal generating means for generating a drive signal driving the vibration exciting means on the basis of an output of the calculating means.
In accordance with a second aspect of the invention in order to achieve the object mentioned above, there is provided a vibration testing system, which is provided with a vibration exciting apparatus for causing a vibration excitation for a prototype model imitating a part of the structure and a digital calculator for calculating a vibration response of a numerical model imaginarily connected to the prototype model, and performs a vibration testing of a whole of the structure, wherein the vibration exciting apparatus is provided with a plurality of vibration exciting means and the plurality of vibration exciting means are arranged in such a manner as to simultaneously apply a translational displacement and a rotational displacement to the prototype model.
Then, preferably, the vibration exciting apparatus has at least three vibration exciting means and includes a horizontal vibration exciting machine for causing a vibration excitation in a horizontal direction and a vertical vibration exciting machine for causing a vibration excitation in a vertical direction and has at least two joints for structurally connecting between the vibration exciting means and the prototype model; a horizontal link is connected to the horizontal vibration exciting means and a vertical link is connected to the vertical vibration exciting means, respectively, and at least one of the horizontal links and at least one of the vertical links are connected to the joint; joint fixing means for fixing the joint to the vibration exciting apparatus is provided and load detecting means capable of detecting loads in at least two different directions is provided between the joint fixing means and the joint; joint fixing means for mounting the prototype model is mounted to the joint and load detecting means capable of detecting at least any one of a load in the different two directions and a moment around an axis is provided in the joint fixing means; there are provided vibration excitation point position calculating means for calculating a position of a point of exciting force from the displacements of a plurality of vibration exciting means, vibration excitation point acceleration estimating means for estimating an acceleration of a point of exciting force on the basis of any one of a displacement, a velocity and an acceleration of at least the vibration exciting means, and a reaction force calculating apparatus for calculating a reaction force of the prototype model on the basis of the acceleration estimated by the vibration excitation point acceleration estimating means, the load detected by the load detecting means and the position of the point of exciting force calculated by the vibration excitation point position calculating means; and there are provided any one of at least acceleration detecting means and angular acceleration detecting means, vibration excitation point velocity and acceleration calculating means for calculating an acceleration of a point of exciting force on the basis of a detected value of any of the detecting means, vibration excitation point position calculating means for calculating a position of a point of exciting force, and reaction force calculating means for calculating a reaction force of the prototype model on the basis of the load detected by the load detecting means, the position of the point of exciting force calculating by the vibration excitation point position calculating means and the acceleration of the point of exciting force calculated by the vibration excitation velocity and acceleration calculating means.
In accordance with a third aspect of the invention in order to achieve the object mentioned above, there is provided a vibration exciting apparatus having a plurality of vibration exciting means for causing a vibration excitation of a body to be tested and a frame for mounting the vibration exciting means, wherein the plurality of vibration exciting means are arranged in such a manner as to simultaneously apply a translational displacement and a rotational displacement to the body to be tested.
Then, preferably, there are provided at least three vibration exciting means and there are included a horizontal vibration exciting machine for causing a vibration excitation in a horizontal direction and a vertical vibration exciting machine for causing a vibration excitation in a vertical direction; there are provided at least two joints for capable of structurally connecting between a body to be tested and the vibration exciting means; a horizontal link is connected to the horizontal vibration exciting means and a vertical link is connected to the vertical vibration exciting means, respectively, and at least one of the horizontal links and at least one of the vertical links are connected to the joint; there is provided joint fixing means for fixing the joint and load detecting means capable of detecting loads in at least two different directions and a moment around one axis is provided in the joint fixing means; there are provided vibration excitation point acceleration estimating means for estimating an acceleration of a point of exciting force on the basis of any one of at least a displacement, a velocity and an acceleration with respect to the horizontal vibration exciting machine and the vertical vibration exciting machine, vibration excitation point position calculating means for calculating a position of a point of exciting force from the displacements of the horizontal vibration exciting machine and the vertical vibration exciting machine, and reaction force calculating means for calculating a reaction force from the body to be tested on the basis of the load detected by the load detecting means, the position of the point of exciting force calculated by the vibration excitation point position calculating means and the acceleration of the point of exciting force estimated by the vibration excitation point acceleration estimating means; and there are provided any one of at least acceleration detecting means and angular acceleration detecting means, vibration excitation point velocity and acceleration calculating means for calculating an acceleration of a point of exciting force on the basis of a detected value of any of the detecting means, vibration excitation point position calculating means for calculating a position of a point of exciting force, and reaction force calculating means for calculating a reaction force of the prototype model on the basis of the load detected by the load detecting means, the position of the point of exciting force calculating by the vibration excitation point position calculating means and the acceleration of the point of exciting force calculated by the vibration excitation velocity and acceleration calculating means.